Makes a whole lot of sense to me, Chas, thanks.
i had that EXACT same realization!
i agree with the rest of what you said, about the pro’s and cons of each.
Listen to what Seamus plays on the CD-rom and try to match his playing. Don’t think about T’s and K’s. Get the feel for the tune, get the rhythm and play it with as powerful a tone as you can master. Rythm first, then ornamentation (and no classical thinking here), and then speed.
This is really good advice, thanks, Bjorn. There is a wealth of solid guidance in this thread.
Does anyone have Video/sound files to demonstrate the different effects. Vallely describes the K thing as a “ch” which is a bit softer sounding than “k”. Im new to the flute world. 
Ballygo
One little thing that kind of irks me: when you make a K sound (such as when you make the “ku” sound when double- or triple-tonguing), it’s not actually a glottal stop, but in fact a velar stop. A true glottal stop is what you hear in place of a “t” when someone with a Cockney accent says the word “bottle.” The almost cough-like plosive sound favored by some Irish flute players is more likely a uvular or perhaps pharygeal stop (or possibly voiceless fricative, depending on whether you fully obstruct the airway or not when doing it…), but I seriously doubt if many flute players out there are really making any articulations that are genuinely glottal…
-The Sporting Pitchfork
Phonetics Vigilante
I don’t want to sound pedantic, but it is physically impossible to articulate a pharyngeal stop.
My understanding was that constriction in the uvular/pharyngeal region was particularly harmful for the sound, on any woodwind 
Putting whether it is "harmful to the sound " and the question of what the correct phonetic/physiological descriptive term may be aside (and I do think it is advantageous to use a correct description, which clearly “glottal” isn’t), if one is seeking to explain, demonstrate or teach the technique used by many ITM players, or indeed just establish for one’s own satisfaction what is going on, try the following:
Whistle - perfectly ordinary lip whistling - get a good sustained sound on one note going. Then put the tip of your thumb and forefinger gently to the sides of your “Adam’s Apple”. Now whistle a few different notes, perhaps part of a scale, not changing notes too quickly and trying not to “articulate” them at all. To do so and not just glissando you will have to use small diaphragm/abdomen “huffs” to stop and start or slightly accent the airstream: you should not feel anything at all with your finger and thumb. (Edit: concentrate on keeping the whole airway, especially low in the throat, open and relaxed.)
Now, if you can (it isn’t easy without practicing), do the same thing separating the notes with conventional “t” tonguing - you’ll have to do it very lightly (striking the forward part of the roof of the mouth about 1cm rearwards of the teeth) or you’ll probably “lose” your whistle tone: still nothing to feel at the Adam’s Apple (but observe the other physical sensations in your mouth, throat and whole air column).
Next, do the same again with “k” and/or “g” articulation (again analysing what your tongue is doing in relation to your whole mouth structure and the airstream) - you should still feel very little at the Adam’s Apple - maybe just a few shock waves.
Finally, do what probably comes most naturally (and which may have been difficult NOT to do in Stage 1), repeat your note sequence with the little low-in-the-throat throat-clearing coughlet for articulation that is what is usually mistitled “glottal” articulation - do it very gently, but you should clearly feel movement, or the shock waves of local movement, with your finger and thumb. If you place your finger tips lower on your throat, below the gristly protrusion of the Adam’s Apple where there is a bulge (still part of the “voice-box”), you should also feel these movements there. In both positions, still also analyse the direct sensations of what is going on in your throat.
Incidentally, the last kind of articulation can quite readily be done whilst generally maintaining a relaxedly open airway for the purposes of supporting a resonant tone - the closures of the vocal chords to interrupt the airstream need not involve permanent tension or constriction of the tubes.
Additionally when whistling, you can for fun try them all “on the suck” as well as “on the blow”! Then go try them on your flute (“blow” only!).
Although I am not a proponent of this throat articulation to the exclusion of tonguing in ITM, and rarely deliberately use it, I suspect (from trying to monitor my own playing) that I actually use it quite a bit (or at least, a gentle, non-percussive form of it) and have always done so without really knowing it, as a kind of carry-over from whistling.
Hope that little exercise may be useful/illuminating! I’ll be interested in any feedback.
Anyone for flutter-tonguing whilst whistling?
EDIT: since I wrote the above early this evening, I’ve been experimenting whilst driving around at work - I’ve concluded that a lot of the time it is easier to feel what is going on in the relevant part of the throat by touching with the finger tips rather lower than I said above - just above the hollow of the throat, on the main bit of the voicebox/pharynx, rather than on the gristly protuberance of the Adam’s Apple.
Also, for the assiduous, it is interesting to make similar observations about what is going on in the mouth and the aircolumn when using any other variations of tongued articulation - all the Baroque “too-roo”, “diddle”, “duh-guh” etc. possibilities.
It’s also interesting to try the fingers-on the pharynx observations whilst singing!
Thanks, Jem, this is a really great explanation, and the exercises you suggest really help to differentiate what’s happening physiologically. I never thought my simple question would yield so much interesting information.
Oops. Quite right. That’s what I get for posting without my IPA chart in front of me…And yes, it doesn’t make sense that people would be articulating much from below the velar region, but I was seized by doubt that maybe it could be. My mistake.
I did this, for six months, sort of on a dare from my teacher (my one official formal lesson, and boy was it worth it!).
I quit tonguing completely, for almost a year. In the interim I figured out other ways to articulate, with articulation, or melodic variations, and also glottal stops. I still have a long way to go with these, but at least my tongue isn’t so quick to get in the way.
As a learner, I’d recommend this. It has helped me get a little further towards playing the way I want to.
Jennie
Does your mother know that you use language like that? 
I think I’ll add that to my list of non-curse words that can still probably get you thumped at the bar, lol.
Disclaimer: I am by far not an expert, but the way I see it, it’s like this (at least it’s my approach to it): ITM is to my great delight very “free” and not as “rigid” as classical music. I mean - for example - if some passage is very difficult for your fingers, just insert/play some other notes that go with the tune. If you need space for a breathing-break, find a good spot and simply don’t play the note at that point. If you make a mistake - don’t worry - play on and find your way back into the tune. It’s almost like mistakes are a part of the genre (at least for me 
). And so on… It’s also “free” in the sense that amateurs come together for sessions, playing all kinds of instruments - I’ve even seen a guy playing spoons So - it’s all good as long as you contribute to the swing and fun of it.
But - on the other hand some “puritans” lurk around saying stuff like “NO tounging what-so-ever”, “NO sheet-music what-so-ever”, “NO boehm-flutes at my session” and so on - and I think this conflicts with the “free” spirit of it - at least of the amateur side of ITM. If you listen to the Wooden Flute Obsession CD’s you can hear all the different approaches/genres of ITM - some are soft and melodical, some harder and edgy and so on… They are SO different. Anything goes! (Well almost, anyway ).
Now, I can appreciate a person wanting to learn the core of ITM - playing as authentic as possible. Nothing wrong with that. If that means no tounging for example - fine. But if you want to play - as I want to - for the sheer fun of it; to learn tunes and play with friends and enjoy the journey - then who cares if you use tounging once in a while in a set?! So what if you and your friends use sheet-music to get going?! It’s better than NOT playing
I have NO problem with people emphasizing authentic playing, but the single most important thing is to play and have fun. Anything goes (almost) - it’s part of the “free” spirit of the music, so don’t let the “NO this…” and “NO that…” hold you back
My 2 cents - as stated I’m no expert, so…
Reading back through this discussion I still don’t find it clear what some of the people posting or the people they are quoting are referring to, although it seems that there is more than one thing being talked about.
What I do in my throat when lip whistling is what jemtheflute describes, and it is the same or extremely similar to what I do when trying to imitate a cockney saying ‘bottle’ (as in Sporting Pitchfork’s post). It seems to me to be what is described here http://en.wikipedia.org/wiki/Glottal_stop which amongst other things mentions it as ‘present in nearly all dialects of English as an allophone of /t/’. Googling that phrase comes up with a glottal stop sometimes being used in mitten, kitten and button; trying that I end up with the same as the cockney bottle. So I am inclined to think that ‘glottal stop’ is the correct term used in linguistics for this. The tongue is not involved.
Trying to do any of the other articulations seems to involve my tongue, from a thing right back at the root of my tongue (that I suspect would make it sore the way an infection can if I did it too much) through several other things to right at the front with tip against the teeth.
Norcalbob’s reference to Seamus Eagan in the OP “glottall stops where he interrupts the airflow by briefly making a gutteral K sound in the back of the throat” and daiv’s reference to Fintan Vallely and “glottal tonguing (which is with your throat, different than a k)” are both confusing.
I think jemthflute’s post clarifies things a lot. But when it comes to playing irish flute I am still not clear what is and is not being recommended. cocusflute’s first post tells me nothing other than that he thinks it is important. It seems that tonguing as in consonents of english speech (g, k, t, d) is what most people are saying not to do too much of. But how about ‘gutteral root of tongue’ and ‘lip whistling’ control of air flow ?
I tongue and shape my mouth quite a lot when playing the whistle but in 8 months on flute it has never occurred to me to tongue. I think I do a lot of ‘lip whistling’ type articulations, but when doing jemtheflute’s ‘exercises’ I realised that I do more diaphragm pushing when lip whistling that I used to so guess I am doing that rather a lot on flute.
I ask this not because I am too bothered about ‘correct irish style’ but to find out what those who make the sort of noises I would like to make are doing.
Edit - typos